A synchronous machine has a stator and a rotor supported in the inner periphery of the stator, is capable of being locally excited and is structurally the same as the stator of a common induction machine. Generally, the synchronous reluctance machine is well known as a motor, which is simply structured and does not need electric current channels or permanent magnets in the rotor. For example, the conventional induction machine comprises a machine body serving as a casing, a stator arranged along an inner circumferential surface of the machine body and an AC squirrel cage rotor rotatably arranged based on a rotational shaft at the center of the stator. The stator is formed of a lamination structure of a plurality of silicon steel and is provided with a plurality of teeth therein. A plurality of slots are formed between the teeth with a certain interval and the coil is wound on the teeth through the slots.
The synchronous reluctance rotor generally includes a plurality of rotor sections formed of alternating magnetic and non-magnetic laminations secured to a unitary core. The core has a central axial bore for receiving a shaft. The laminations are inserted between radially extending arms of the core that are formed with a smooth, arcuate recess therebetween. The laminations are secured in the recesses by means of radial fasteners that secure radially opposing rotor sections to the core. The rotor sections are also secured together by end caps and radial fasteners. The end caps are cup-shaped members with an axially extending outer rim that is disposed about the outermost periphery of the laminations. The radial fasteners extend through the end caps and core to secure the end caps to the rotor. The rotor laminations may also be bonded to one with another and to the core using an epoxy or other adhesive material.
Existing synchronous reluctance machines are mechanically and thermally limited due to the use of “boat” shaped laminations, stacked radially for the rotor. Traditionally, the synchronous reluctance machines have a rotor shaft that has been machined to receive the boat shaped laminations stacked radially along the rotor shaft. The boat shaped lamination poles are then bolted to the rotor shaft. This construction limits the rotor dimensions for high-speed applications and inherently has significant core losses. Attempts in the past to remedy this problem have been to select alternate machine topology and not to address the problem directly.